The present invention relates to a computer system and, more particularly, a multi-purpose compatible computer system which can provide optimum functions for different purposes with a single computer system.
With the recent trends of office automation (OA), user needs have diversed in a variety of applications. When users introduce OA equipment, its effective use as well as its convenience in handling has been discussed. Personal computers and wordprocessors have similar hardware architectures. It is therefore common to add a function of one equipment to the other, i.e., a personal computer function to a wordprocessor or vice versa.
The above functional compatibility is achieved by software in conventional systems. For example, in order to add wordprocessor functions to a personal computer, wordprocessor software (or application software) which operates on a personal compter OS (operating system) is loaded, or an IPL (initial program loader) of the personal computer is utilized to load the wordprocessor software instead of the personal computer OS. In order to add personal computer functions to a wordprocessor, a method opposite to the above can be used.
If different equipment have the same purposes, like different game machines, the compatibility can be attained by only exchanging software. However, since personal computers and wordprocessors are designed for different purposes, they have different hardware features. Therefore, when compatibility is to be achieved for these equipments, software exchange cannot provide satisfactory special purpose, resulting in drawbacks as follows:
1. Sufficient compatibility with conventional equipment cannot be obtained, resulting in functional degradation.
2. Development for software for achieving compatibility takes much time, and special-purpose software must be altered greatly.
When a new model of a personal computer is to be developed, it necessarily has compatibility with the old models. Software developed for the old model must run on the new model. For this purpose, at least a memory address map and an input/output address map of the new model must be the same as those of the old model, thereby interfering with addition of a new function.